code: def test_with_an_underscore_and_a_comma_in_format_specifier(self):
      error_msg = re.escape("Cannot specify both ',' and '_'.")
      with self.assertRaisesRegex(ValueError, error_msg):
          "{:_,}".format(1)
  
imports: from test.support import verbose, TestFailed
  import locale
  import sys
  import re
  import test.support
  import unittest
label_desc: Use image node_id 14 for calling the FormatTest obj's underlying member method code with example usage: obj.test_with_an_underscore_and_a_comma_in_format_specifier() without return types